What Causes Sore Breasts And Bloated Stomach When On Mirena Coil?

Hi i had the mirena coil fitted almost 5 yrs ago,my periods stopped when i got it but in december/january i had spotting like the start of a period that stopped as soon as it started as such, lately my breasts are extremely sore and my stomach is fairly big lately, i tried to see if i could feel the strings of my coil to make sure its in place but i never checked before so couldnt feel anything my doctor did a pregnancy test which was negative and im waitin on blood test results to determine if i am pregnant, what are the chances?